Internal combustion engines are machines that provide mechanical energy and functionality to products such as industrial equipment and vehicles. They are fundamentally based on the combustion of a combustible/comburent mixture inside a chamber, which can be ignited by sparks or high temperature.
Types of internal combustion engines: among the engines known as economically reliable and widely commercialized, the engines that present a significantly high demand are the ones applied to vehicles:
a) Two-stroke-cycle engine: an engine that provides high rotation and, consequently, high power. Its operation may be understood by the two-stroke-cycle necessary to conclude a complete turn of the crankshaft. A disadvantage of this type of engine is that to obtain high power, it has a high consumption of combustible fuel. This results in a high emission rate of toxic gases and particulate matter in the atmosphere, which makes this type of engine unsuitable for use in ecologically friendly products.
b) Four-stroke-cycle engine: provides high power at relatively low rotations, when compared to the two-stroke-cycle engine, but its manufacturing requires a great number of static and dynamic parts. Its operation requires two complete turns of the crankshaft to complete a cycle. Despite being more economical from a point of view of fuel consumption, these engines present a high vibration level, high mechanical losses, as well as a great number of component parts, which means this type of engine has higher manufacturing costs, as well as high maintenance costs and a high probability of failure.
c) Diesel engine: this type of engine operates based on the absorption of atmospheric air inside the combustion chamber, where its internal temperature is increased to more than 600° C., and where the combustible (diesel) is directly injected inside the chamber and starts the explosion process. Contrary to piston rotary engines, and non-diesel two-stroke-cycle and four-stroke-cycle engines, this type of engine does not need a spark system to start the combustion process. However, they produce a high emission rate of gases and particulate matter in the atmosphere. They also present very intensive vibrations and they necessarily need a construction that makes them heavy and noisy, mainly due to the high compression rates.
d) Rotary engine: this type of engine has a simpler design compared to piston rotary engines. A rotary engine has a rotor (or rotors) that rotates inside a jacket. Rotary engines are generally extremely compact and light. However, application to vehicles has faced regulatory restrictions largely due to its combustible fuel consumption and pollutant emission rates.
Other types of engines include, jet engines; turbines (gas and aeronautic) and rocket engines.
Several embodiments of rotary engines exist that use the concept of an internal combustion engine. There is a lot of technical literature that demonstrates that almost all of these embodiments present the basic concept of the rotary engine idealized, patented and constructed by Felix Wankel in the 1940s. We can observe generally, that all these “Wankel” engines present the same problem of non-constant perpendicularity between the chamber divisors and the jacket. This considerably impairs the sealing and internal cleaning, which results in a dirty and non-economical engine, that prevents the large scale production of these engines.
Wankel engine: this rotary engine has a single jacket, which describes a cavity whose profile approximately represents a figure 8-shape, which contains an assembled rotor, having an approximately triangular shape that in a general way has the function of a piston component, used in conventional alternative combustion engines. The rotor is assembled on a rotational axis, mainly an equivalent axis to a crankshaft component.
In order to assure the necessary sealing for an efficient explosion cycle, a discreet sealing element is added on the end of each edge formed in the triangular rotor.
Operational principle of the Wankel engine: this engine presents a four-stroke-cycle: intake, compression, combustion and exhaust. In order to obtain this cycle the triangular rotor turns eccentrically in relation to the axis of the crankshaft component (main axis), making the edges of the triangular rotor describe a movement that is equidistant from the wall of the cavity (or jacket) of the chamber.
This eccentric displacement of the triangular rotor results in an increase or decrease of the space between the convex sides of the rotor and the wall of the cavity of the jacket. When this space is increasing, a combustible/comburent mixture is injected inside the chamber and is compressed during the subsequent decrease of the volume of the chamber, thus, creating the cycle, mainly the classical four-stroke-cycle previously mentioned.
Advantages of the Wankel rotary engines: several positive characteristics can be highlighted: reduced vibration levels during its operation, due to its reduced number of interactive components, as well as the absence of movement inversion of defined components in the mechanism;
Due to its reduced number of component parts, it presents a compact assembly that makes it easier to assemble in equipment and/or vehicles and also allows for a lower gravity center of the vehicle, which in turn allows an increase in the degrees of freedom in the aerodynamic nature of the designs;                It presents superior rotation and torque;        It may present combustible consumption similar or equivalent to piston rotary engines, and        A more flexible power curve, when compared with the power curve of piston rotary engines.        
Disadvantages of the Wankel rotary engines: Wankel rotary engines present the following negative characteristics:                Impairment of their reliability due to deficient sealing systems on the edges of the triangual rotor and walls of the cavities of the chamber (jacket);        Impairment of the durability due to its deficient sealing between static (jacket) and movable (rotor triangular/sealing) components that results in the formation and accumulation of particulate matter;        Excessive engine heating due to the great internal area of the chamber, resulting in great heat exchange between the hot gas and the housing (jacket);        A limited number of chambers and a unique possible relation between the fixed gear and the dynamic gear, fixed to the rotor; and        It necessitates a high-precision assembly of the involved components, with very restrictive tolerances—practically nominal measures.        
As we can see from the above description, it is a fact that the solution of the rotary “Wankel” engine accomplishes the primary objective, which is converting thermal energy in mechanical energy to provide movement to industrial equipment or a vehicle. However, it is a fact that these solutions present deficient aspects, mainly the obtainment of distinct reliability, durability and quality.
Current rotary engines have a deficient sealing system between the chambers, i.e., their form does not allow an ideal operation of the seals that separate the chambers, impairing the sealing at the contact point among the static and dynamic components of the engine. The figure 8-shape profile of the jacket cavity does not permit constant perpendicularity between the discreet stem of the sealing element and the wall of the cavity of the jacket in its whole outline, where this perpendicularity only occurs in discreet points of the cavity, when the rotor describes its eccentric movement. Thus, there are moments when the sealing between the discreet stem of the sealing element and the wall of the cavity of the jacket is deficient, since the known sealing element presents design and functional characteristics that limit its efficiency. In the case of the Wankel engine, for example, this sealing element presents four unique conditions of perpendicularity between the discreet sealing element and the cavity of the jacket (as will be discussed below). It can be seen that the contact between the discreet sealing element in the edge of the rotor and the cavity (chamber), in the complete sequence of the cycle, is oblique and forms several contact angles. Such occurrence significantly impairs the efficiency of the sealing between the chambers.
Thus, the limited efficiency of the sealing system compromises the performance of the internal chambers during the classical cycle of intake, compression, explosion and exhaustion, a fact that produces several other functional problems with durability, efficiency, reliability, consumption and pollutant emission.
Therefore, there is a need for a rotary engine having the desirable attributes of excellent tightness between chambers, durability, reliability with high yield, low mechanical losses, and whose manufacture is industrially and economically possible for all classes of engines that present the concept of transforming energy from a chemical reaction to mechanical energy through the cycle of intake, compression, explosion/expansion and exhaust/flow of a combustible/comburent mixture inside the combustion chambers, which presents superior or equal operational life when compared to the traditional piston rotary engines.
There is also a need for a rotary engine that offers lower consumption of combustible that translates in a reduction of the gas volume and particulate matter exhausted by the functional cycle of the engine.
There is also a need for a rotary engine that presents low levels of noise and vibration, providing comfort to the users of the equipment which is driven by the engine, mainly to drivers and passengers of vehicles, or to operators of equipment.
There is also a need for a rotary engine that can be manufactured at a cost almost equivalent, or even lower than the cost of manufacturing rotary engines, such as the “Wankel”-type rotary engines.